net/sched/sch_prio.c

   1 /*
   2  * net/sched/sch_prio.c Simple 3-band priority "scheduler".
   3  *
   4  *              This program is free software; you can redistribute it and/or
   5  *              modify it under the terms of the GNU General Public License
   6  *              as published by the Free Software Foundation; either version
   7  *              2 of the License, or (at your option) any later version.
   8  *
   9  * Authors:     Alexey Kuznetsov, <kuznet@ms2.inr.ac.ru>
  10  * Fixes:       19990609: J Hadi Salim <hadi@nortelnetworks.com>:
  11  *              Init --  EINVAL when opt undefined
  12  */
  13
  14 #include <linux/module.h>
  15 #include <linux/slab.h>
  16 #include <linux/types.h>
  17 #include <linux/kernel.h>
  18 #include <linux/string.h>
  19 #include <linux/errno.h>
  20 #include <linux/skbuff.h>
  21 #include <net/netlink.h>
  22 #include <net/pkt_sched.h>
  23 #include <net/pkt_cls.h>
  24
  25 struct prio_sched_data {
  26         int bands;
  27         struct tcf_proto __rcu *filter_list;
  28         struct tcf_block *block;
  29         u8  prio2band[TC_PRIO_MAX+1];
  30         struct Qdisc *queues[TCQ_PRIO_BANDS];
  31 };
  32
  33
  34 static struct Qdisc *
  35 prio_classify(struct sk_buff *skb, struct Qdisc *sch, int *qerr)
  36 {
  37         struct prio_sched_data *q = qdisc_priv(sch);
  38         u32 band = skb->priority;
  39         struct tcf_result res;
  40         struct tcf_proto *fl;
  41         int err;
  42
  43         *qerr = NET_XMIT_SUCCESS | __NET_XMIT_BYPASS;
  44         if (TC_H_MAJ(skb->priority) != sch->handle) {
  45                 fl = rcu_dereference_bh(q->filter_list);
  46                 err = tcf_classify(skb, fl, &res, false);
  47 #ifdef CONFIG_NET_CLS_ACT
  48                 switch (err) {
  49                 case TC_ACT_STOLEN:
  50                 case TC_ACT_QUEUED:
  51                 case TC_ACT_TRAP:
  52                         *qerr = NET_XMIT_SUCCESS | __NET_XMIT_STOLEN;
  53                         /* fall through */
  54                 case TC_ACT_SHOT:
  55                         return NULL;
  56                 }
  57 #endif
  58                 if (!fl || err < 0) {
  59                         if (TC_H_MAJ(band))
  60                                 band = 0;
  61                         return q->queues[q->prio2band[band & TC_PRIO_MAX]];
  62                 }
  63                 band = res.classid;
  64         }
  65         band = TC_H_MIN(band) - 1;
  66         if (band >= q->bands)
  67                 return q->queues[q->prio2band[0]];
  68
  69         return q->queues[band];
  70 }
  71
  72 static int
  73 prio_enqueue(struct sk_buff *skb, struct Qdisc *sch, struct sk_buff **to_free)
  74 {
  75         struct Qdisc *qdisc;
  76         int ret;
  77
  78         qdisc = prio_classify(skb, sch, &ret);
  79 #ifdef CONFIG_NET_CLS_ACT
  80         if (qdisc == NULL) {
  81
  82                 if (ret & __NET_XMIT_BYPASS)
  83                         qdisc_qstats_drop(sch);
  84                 __qdisc_drop(skb, to_free);
  85                 return ret;
  86         }
  87 #endif
  88
  89         ret = qdisc_enqueue(skb, qdisc, to_free);
  90         if (ret == NET_XMIT_SUCCESS) {
  91                 qdisc_qstats_backlog_inc(sch, skb);
  92                 sch->q.qlen++;
  93                 return NET_XMIT_SUCCESS;
  94         }
  95         if (net_xmit_drop_count(ret))
  96                 qdisc_qstats_drop(sch);
  97         return ret;
  98 }
  99
 100 static struct sk_buff *prio_peek(struct Qdisc *sch)
 101 {
 102         struct prio_sched_data *q = qdisc_priv(sch);
 103         int prio;
 104
 105         for (prio = 0; prio < q->bands; prio++) {
 106                 struct Qdisc *qdisc = q->queues[prio];
 107                 struct sk_buff *skb = qdisc->ops->peek(qdisc);
 108                 if (skb)
 109                         return skb;
 110         }
 111         return NULL;
 112 }
 113
 114 static struct sk_buff *prio_dequeue(struct Qdisc *sch)
 115 {
 116         struct prio_sched_data *q = qdisc_priv(sch);
 117         int prio;
 118
 119         for (prio = 0; prio < q->bands; prio++) {
 120                 struct Qdisc *qdisc = q->queues[prio];
 121                 struct sk_buff *skb = qdisc_dequeue_peeked(qdisc);
 122                 if (skb) {
 123                         qdisc_bstats_update(sch, skb);
 124                         qdisc_qstats_backlog_dec(sch, skb);
 125                         sch->q.qlen--;
 126                         return skb;
 127                 }
 128         }
 129         return NULL;
 130
 131 }
 132
 133 static void
 134 prio_reset(struct Qdisc *sch)
 135 {
 136         int prio;
 137         struct prio_sched_data *q = qdisc_priv(sch);
 138
 139         for (prio = 0; prio < q->bands; prio++)
 140                 qdisc_reset(q->queues[prio]);
 141         sch->qstats.backlog = 0;
 142         sch->q.qlen = 0;
 143 }
 144
 145 static int prio_offload(struct Qdisc *sch, struct tc_prio_qopt *qopt)
 146 {
 147         struct net_device *dev = qdisc_dev(sch);
 148         struct tc_prio_qopt_offload opt = {
 149                 .handle = sch->handle,
 150                 .parent = sch->parent,
 151         };
 152
 153         if (!tc_can_offload(dev) || !dev->netdev_ops->ndo_setup_tc)
 154                 return -EOPNOTSUPP;
 155
 156         if (qopt) {
 157                 opt.command = TC_PRIO_REPLACE;
 158                 opt.replace_params.bands = qopt->bands;
 159                 memcpy(&opt.replace_params.priomap, qopt->priomap,
 160                        TC_PRIO_MAX + 1);
 161                 opt.replace_params.qstats = &sch->qstats;
 162         } else {
 163                 opt.command = TC_PRIO_DESTROY;
 164         }
 165
 166         return dev->netdev_ops->ndo_setup_tc(dev, TC_SETUP_QDISC_PRIO, &opt);
 167 }
 168
 169 static void
 170 prio_destroy(struct Qdisc *sch)
 171 {
 172         int prio;
 173         struct prio_sched_data *q = qdisc_priv(sch);
 174
 175         tcf_block_put(q->block);
 176         prio_offload(sch, NULL);
 177         for (prio = 0; prio < q->bands; prio++)
 178                 qdisc_destroy(q->queues[prio]);
 179 }
 180
 181 static int prio_tune(struct Qdisc *sch, struct nlattr *opt,
 182                      struct netlink_ext_ack *extack)
 183 {
 184         struct prio_sched_data *q = qdisc_priv(sch);
 185         struct Qdisc *queues[TCQ_PRIO_BANDS];
 186         int oldbands = q->bands, i;
 187         struct tc_prio_qopt *qopt;
 188
 189         if (nla_len(opt) < sizeof(*qopt))
 190                 return -EINVAL;
 191         qopt = nla_data(opt);
 192
 193         if (qopt->bands > TCQ_PRIO_BANDS || qopt->bands < 2)
 194                 return -EINVAL;
 195
 196         for (i = 0; i <= TC_PRIO_MAX; i++) {
 197                 if (qopt->priomap[i] >= qopt->bands)
 198                         return -EINVAL;
 199         }
 200
 201         /* Before commit, make sure we can allocate all new qdiscs */
 202         for (i = oldbands; i < qopt->bands; i++) {
 203                 queues[i] = qdisc_create_dflt(sch->dev_queue, &pfifo_qdisc_ops,
 204                                               TC_H_MAKE(sch->handle, i + 1),
 205                                               extack);
 206                 if (!queues[i]) {
 207                         while (i > oldbands)
 208                                 qdisc_destroy(queues[--i]);
 209                         return -ENOMEM;
 210                 }
 211         }
 212
 213         prio_offload(sch, qopt);
 214         sch_tree_lock(sch);
 215         q->bands = qopt->bands;
 216         memcpy(q->prio2band, qopt->priomap, TC_PRIO_MAX+1);
 217
 218         for (i = q->bands; i < oldbands; i++) {
 219                 struct Qdisc *child = q->queues[i];
 220
 221                 qdisc_tree_reduce_backlog(child, child->q.qlen,
 222                                           child->qstats.backlog);
 223                 qdisc_destroy(child);
 224         }
 225
 226         for (i = oldbands; i < q->bands; i++) {
 227                 q->queues[i] = queues[i];
 228                 if (q->queues[i] != &noop_qdisc)
 229                         qdisc_hash_add(q->queues[i], true);
 230         }
 231
 232         sch_tree_unlock(sch);
 233         return 0;
 234 }
 235
 236 static int prio_init(struct Qdisc *sch, struct nlattr *opt,
 237                      struct netlink_ext_ack *extack)
 238 {
 239         struct prio_sched_data *q = qdisc_priv(sch);
 240         int err;
 241
 242         if (!opt)
 243                 return -EINVAL;
 244
 245         err = tcf_block_get(&q->block, &q->filter_list, sch, extack);
 246         if (err)
 247                 return err;
 248
 249         return prio_tune(sch, opt, extack);
 250 }
 251
 252 static int prio_dump_offload(struct Qdisc *sch)
 253 {
 254         struct net_device *dev = qdisc_dev(sch);
 255         struct tc_prio_qopt_offload hw_stats = {
 256                 .command = TC_PRIO_STATS,
 257                 .handle = sch->handle,
 258                 .parent = sch->parent,
 259                 {
 260                         .stats = {
 261                                 .bstats = &sch->bstats,
 262                                 .qstats = &sch->qstats,
 263                         },
 264                 },
 265         };
 266         int err;
 267
 268         sch->flags &= ~TCQ_F_OFFLOADED;
 269         if (!tc_can_offload(dev) || !dev->netdev_ops->ndo_setup_tc)
 270                 return 0;
 271
 272         err = dev->netdev_ops->ndo_setup_tc(dev, TC_SETUP_QDISC_PRIO,
 273                                             &hw_stats);
 274         if (err == -EOPNOTSUPP)
 275                 return 0;
 276
 277         if (!err)
 278                 sch->flags |= TCQ_F_OFFLOADED;
 279
 280         return err;
 281 }
 282
 283 static int prio_dump(struct Qdisc *sch, struct sk_buff *skb)
 284 {
 285         struct prio_sched_data *q = qdisc_priv(sch);
 286         unsigned char *b = skb_tail_pointer(skb);
 287         struct tc_prio_qopt opt;
 288         int err;
 289
 290         opt.bands = q->bands;
 291         memcpy(&opt.priomap, q->prio2band, TC_PRIO_MAX + 1);
 292
 293         err = prio_dump_offload(sch);
 294         if (err)
 295                 goto nla_put_failure;
 296
 297         if (nla_put(skb, TCA_OPTIONS, sizeof(opt), &opt))
 298                 goto nla_put_failure;
 299
 300         return skb->len;
 301
 302 nla_put_failure:
 303         nlmsg_trim(skb, b);
 304         return -1;
 305 }
 306
 307 static int prio_graft(struct Qdisc *sch, unsigned long arg, struct Qdisc *new,
 308                       struct Qdisc **old, struct netlink_ext_ack *extack)
 309 {
 310         struct prio_sched_data *q = qdisc_priv(sch);
 311         struct tc_prio_qopt_offload graft_offload;
 312         struct net_device *dev = qdisc_dev(sch);
 313         unsigned long band = arg - 1;
 314         bool any_qdisc_is_offloaded;
 315         int err;
 316
 317         if (!new) {
 318                 new = qdisc_create_dflt(sch->dev_queue, &pfifo_qdisc_ops,
 319                                         TC_H_MAKE(sch->handle, arg), extack);
 320                 if (!new)
 321                         new = &noop_qdisc;
 322                 else
 323                         qdisc_hash_add(new, true);
 324         }
 325
 326         *old = qdisc_replace(sch, new, &q->queues[band]);
 327
 328         if (!tc_can_offload(dev))
 329                 return 0;
 330
 331         graft_offload.handle = sch->handle;
 332         graft_offload.parent = sch->parent;
 333         graft_offload.graft_params.band = band;
 334         graft_offload.graft_params.child_handle = new->handle;
 335         graft_offload.command = TC_PRIO_GRAFT;
 336
 337         err = dev->netdev_ops->ndo_setup_tc(dev, TC_SETUP_QDISC_PRIO,
 338                                             &graft_offload);
 339
 340         /* Don't report error if the graft is part of destroy operation. */
 341         if (err && new != &noop_qdisc) {
 342                 /* Don't report error if the parent, the old child and the new
 343                  * one are not offloaded.
 344                  */
 345                 any_qdisc_is_offloaded = sch->flags & TCQ_F_OFFLOADED;
 346                 any_qdisc_is_offloaded |= new->flags & TCQ_F_OFFLOADED;
 347                 if (*old)
 348                         any_qdisc_is_offloaded |= (*old)->flags &
 349                                                    TCQ_F_OFFLOADED;
 350
 351                 if (any_qdisc_is_offloaded)
 352                         NL_SET_ERR_MSG(extack, "Offloading graft operation failed.");
 353         }
 354
 355         return 0;
 356 }
 357
 358 static struct Qdisc *
 359 prio_leaf(struct Qdisc *sch, unsigned long arg)
 360 {
 361         struct prio_sched_data *q = qdisc_priv(sch);
 362         unsigned long band = arg - 1;
 363
 364         return q->queues[band];
 365 }
 366
 367 static unsigned long prio_find(struct Qdisc *sch, u32 classid)
 368 {
 369         struct prio_sched_data *q = qdisc_priv(sch);
 370         unsigned long band = TC_H_MIN(classid);
 371
 372         if (band - 1 >= q->bands)
 373                 return 0;
 374         return band;
 375 }
 376
 377 static unsigned long prio_bind(struct Qdisc *sch, unsigned long parent, u32 classid)
 378 {
 379         return prio_find(sch, classid);
 380 }
 381
 382
 383 static void prio_unbind(struct Qdisc *q, unsigned long cl)
 384 {
 385 }
 386
 387 static int prio_dump_class(struct Qdisc *sch, unsigned long cl, struct sk_buff *skb,
 388                            struct tcmsg *tcm)
 389 {
 390         struct prio_sched_data *q = qdisc_priv(sch);
 391
 392         tcm->tcm_handle |= TC_H_MIN(cl);
 393         tcm->tcm_info = q->queues[cl-1]->handle;
 394         return 0;
 395 }
 396
 397 static int prio_dump_class_stats(struct Qdisc *sch, unsigned long cl,
 398                                  struct gnet_dump *d)
 399 {
 400         struct prio_sched_data *q = qdisc_priv(sch);
 401         struct Qdisc *cl_q;
 402
 403         cl_q = q->queues[cl - 1];
 404         if (gnet_stats_copy_basic(qdisc_root_sleeping_running(sch),
 405                                   d, cl_q->cpu_bstats, &cl_q->bstats) < 0 ||
 406             gnet_stats_copy_queue(d, NULL, &cl_q->qstats, cl_q->q.qlen) < 0)
 407                 return -1;
 408
 409         return 0;
 410 }
 411
 412 static void prio_walk(struct Qdisc *sch, struct qdisc_walker *arg)
 413 {
 414         struct prio_sched_data *q = qdisc_priv(sch);
 415         int prio;
 416
 417         if (arg->stop)
 418                 return;
 419
 420         for (prio = 0; prio < q->bands; prio++) {
 421                 if (arg->count < arg->skip) {
 422                         arg->count++;
 423                         continue;
 424                 }
 425                 if (arg->fn(sch, prio + 1, arg) < 0) {
 426                         arg->stop = 1;
 427                         break;
 428                 }
 429                 arg->count++;
 430         }
 431 }
 432
 433 static struct tcf_block *prio_tcf_block(struct Qdisc *sch, unsigned long cl,
 434                                         struct netlink_ext_ack *extack)
 435 {
 436         struct prio_sched_data *q = qdisc_priv(sch);
 437
 438         if (cl)
 439                 return NULL;
 440         return q->block;
 441 }
 442
 443 static const struct Qdisc_class_ops prio_class_ops = {
 444         .graft          =       prio_graft,
 445         .leaf           =       prio_leaf,
 446         .find           =       prio_find,
 447         .walk           =       prio_walk,
 448         .tcf_block      =       prio_tcf_block,
 449         .bind_tcf       =       prio_bind,
 450         .unbind_tcf     =       prio_unbind,
 451         .dump           =       prio_dump_class,
 452         .dump_stats     =       prio_dump_class_stats,
 453 };
 454
 455 static struct Qdisc_ops prio_qdisc_ops __read_mostly = {
 456         .next           =       NULL,
 457         .cl_ops         =       &prio_class_ops,
 458         .id             =       "prio",
 459         .priv_size      =       sizeof(struct prio_sched_data),
 460         .enqueue        =       prio_enqueue,
 461         .dequeue        =       prio_dequeue,
 462         .peek           =       prio_peek,
 463         .init           =       prio_init,
 464         .reset          =       prio_reset,
 465         .destroy        =       prio_destroy,
 466         .change         =       prio_tune,
 467         .dump           =       prio_dump,
 468         .owner          =       THIS_MODULE,
 469 };
 470
 471 static int __init prio_module_init(void)
 472 {
 473         return register_qdisc(&prio_qdisc_ops);
 474 }
 475
 476 static void __exit prio_module_exit(void)
 477 {
 478         unregister_qdisc(&prio_qdisc_ops);
 479 }
 480
 481 module_init(prio_module_init)
 482 module_exit(prio_module_exit)
 483
 484 MODULE_LICENSE("GPL");